Katana

Heh, even my MY93 was running at 1.5 Bar (23 psi) so I think with your STI internals, it would be better..

edit: don't try this at home. I don't want a horde of pr-97 scoobynetters waiting outside of my house wanting my head if something goes wrong.

[Edited by Katana - 12/2/2002 6:34:35 PM]

BoxerFlat4

OK, several points :-

"Inhibitor", I assume you referring to the fuel cut ? This will kick in when the computer decides your running too much boost, which if memory serves me correctly will be around the 1.4 bar level. It will be happening since the downpipe's gone on, because the free flowing downpipe will be allowing slightly more boost then previously, so you'll hit the limit. Options ? As you stated, either a FCD to disable the fuel cut, or a Dawes device or similiar to limit the boost. Dropping the boost down slightly should prevent fuel cut occuring, and with careful adjustement you shouldn't feel any difference power wise. You shouldn't need to drop the boost by much.

Alternatively, use a FCD to remove the fuel cut limit, which will allow you to run full boost. Stress on the engine, especially if a non-STI, will be high at this point upwards, and you should be considering the following :-

1. As many gauges as possible, to keep an eye on engine condition. Personally, I would suggest oil pressure/temperature, boost, air/fuel mixture and a Knock sensor. These will show whats happening internally, and will help warn of any imminent problems !

2. Fuelling : you may already be running too lean, and risking the engines life. Uprated fuel pump would be a wise move, and if you intend to increase power at all, uprated injectors/fuel rails would also be wise. Check you AFR as soon as possible !

What spec car you running at the moment ?

Paul Houbart
Gecko Motosport

[Edited by BoxerFlat4 - 12/2/2002 8:15:44 PM]

Jamie Whitfield

Just thought it should be said that I DID NOT say that power would be the same at 1.1 bar as 1.4, but I did advise that an AFR be fitted to see exactly how the AFR is, then we should drop the boost down to 1.1 bar for safety's sake.

What I think Andrew took from my statement was that I said that boost doesn't neccessarily mean power, as he was under the impression that the only reason for replacing the downpipe was to make more boost, although of course this is only a spike!

Andrew, every car is different, just because one will run 23psi all day long doesn't mean yours will, it is therefore important to put all the precautionary measures in place as I have discussed with you today and as Paul mentions above:

AFR
Boost Controller
Knock Link

I have offered to set the car up for you, please take this opportunity, in the long run it is very cheap compared to a rebuild.

Jamie

www.j-w-racing.com

[Edited by Jamie Whitfield - 12/3/2002 12:02:38 AM]

ronniebiggs

Im running 1.4 bar at the moment without any boost control devices and was told that this is a dangerous amount of boost.
Is there a noticeable difference between 1.1 and 1.4 bar in terms of peformance and which should I run.

I will have to fit a Dawes to restrict boost if I have to lower the boost.

Any help or thoughts on this issue would be appreciated.
Regards Ronnie

LG John

What car, what mods?

BoxerFlat4

My car's running 19PSI, 1.3 BAR without any problems. If yours is a UK car, then your pushing the internals a bit, but in my (limited) experience I wouldn't of thought you'd hit any major problems. Are you getting ay boost spikes ?

MY94 STI 1

5 Type R

Performance should be consisderably better running 1,4 bar compared to 1.1.................
I achieved approx 40% increase in torque when my Type R was remapped to peak at 1.4bar.........

Have you had the car remapped for the boost?????

IMO its not a good idea to start messing around with boost pressures unless you get the fuelling and ignition mapped accordingly.

ronniebiggs

Sorry for taking so long to reply,
The car has An Unisia Jecs 'MINES' ecu and I think a HKS dragster full system, Magnex downpipe, no-cats, K+N induction kit. I dont know what u mean by spikes?

I peak at 1.4ish then the inhibitor kicks in. its only started doing this since I fitted the downpipe. Dont know what internals are in the engine but I think quite alot of the car is MINES tuned.

Boost seems fine, until 4th and 5th then if you plant your foot to the floor you hit the inhibitor. Was going to put either a DAWES on to limit the boost down or a fuel cut raiser to stop the limiter.

Jamie Whitfield from J-W-racing advises me tolimit the boost to 1 bar and said the power would be the same at 1.4 or 1.1 bar boost.
Many thanks to all
Ronnie

LG John

How could the power be the same at 1.1 or 1.4 bar? At 1.4bar your sticking more air in, hence more power - assuming the fuel to match is available - if not, boom

ronniebiggs

Thats what I thought,
The ecu should sort fuelling, but Jamie said I want to fit an AFR to make sure fuelling was OK.
It seems OK ive cained it quite alot!!!!

nom

Remember a few points here:
Boost means not a lot. It is a measurement of how much air can't get into the cylinders. What you want is as much oxygen crammed into the cylinders as possible. You could say boost is a measurement of how inefficient your exhaust system is.
Next - turbo efficiency. The standard scoob turbos (bar the big turbo JDM models & TD05 ones) at higher boost generate a lot of heat. This will read as high boost, but the actual charge density (what you want) can actually be lower as the turbo is so inefficient at high pressure ratios.
So, higher boost can be less power.

BoxerFlat4

And, attempting too buch boost can induce detonation, which is quick and deadly to turbo engines.

Pavlo

Ronnies car will have a td05, I wouldn't run 1.4 bar on the standard intercooler, although some do.

You will get more power at 1.4 vs 1.1 on the td05, it can flow rather well, but fuel pump and injectors not up to the job if you're holding that sort of boost much over 5000 rpm.

The STI 1 and 2 don't have uprated internals like the 3 and 4, and even then it was just lighter forged pistons.

Dawes limited to 1.2bar would be good compromise I think, an engine doesn't make much power with a holes piston.

paul

ronniebiggs

Thanks for the replys,
My car is a jap import 1994 WRX running on the large turbo. As I said above it has been played with. The ECU is MINES and Im not sure how to check the fuel rail at this time to see if that is Mines.
Can anyone tell me if there airflow meter says Unisia Jecs on it. As again I think my airflow meter is a big flow MINES meter. I will have a good look over the full car tommorrow and try to find out if anything else has been done. I want to run as high (but reliable) boost as possible. 1.2 was what I was thinking about.

Where is the fuel pump? Is it in the tank? as I will check that in the morning as well?

Many thanks everything that has been said is helpful
Regards Ronnie

ronniebiggs

Very sorry Jamie!! I did misinterpret you. Didnt mean to offend. I got muddled up!!

Jamie Whitfield

No offence at all, just thought I should keep you right! I have a reputation to withhold - not!

Speak to you tomorrow, tell me when you want to come round and I'll see what we can come up with!

Jamie

R19KET

The MINES ECU is a Japanese after market RE-MAPPED ECU.

In theory, the fuel, and ignition will have been re-mapped for the boost.

HOWEVER, it will have been re-mapped for the higher octane Japanese fuel, and this could cause a SERIOUS PROBLEM, if you don't run it on either 97RON/Optimax with octane booster.

I would recommend that you get someone experienced to check the car out, Using a set of det' cans, to make sure it isn't detting, and also get your fuelling checked too. If you don't have a AFR meter, you could ask someone with a "select monitor" to check it, or get it checked on a rolling road.

IF after getting it checked out, it is either detting, or running lean, or you just don't want to run with octane booster all the time, then it would be worth looking at one of the re-mappable options.

It may not just be a case of turning the boost down, or adding more fuel. If the ignition has been re-mapped for a higher octane, it could just as likely det' on cruise, as high loads.

You need to get it checked.

Mark.

Katana

I was naughty, I know.

But I did take all the precautions and my car was used for a different thing.

Let me elaborate though. I'm more into Drag Racing, which means that I won't be on boost for more than 10-13 seconds. If its track days then I'd turn the boost down a bit. Metal fatigue is proportional to both pressure and vibration. The block may take it (no doubt) but the rest of the engine won't be too happy.

Besides, I had some spare parts with me in the past. Thats why I said don't try this at home.

ronniebiggs

I think ill get an AFR now then and make things right!! The actual ECU is Unisia Jecs, with the mines guarentee plaque above. So again. Is this ECU different from standard, then been chipped by MINES?
Also like I said, I will check the car over now and see if the fuelling or anything else has been alterred.

What is a CPU ACD? And where would I find it on the car?
Does the injectors have a seperate computer? if so where can it be found?

What make is the standard Airflow meter on a MY 94 WRX? mine says Unisia Jecs on!!


If I get a reply ill check my car as I think these may also be altered.
Rergards Ronnie

Pavlo

The Unisa Jecs ecu is the standard on scoobs till 01, when they were done by Nippon Denso.

The MINES bit is basically a chip, with new fuel, ignition and boost maps, they wont have touched anything else on the car, the unit is an exchange ECU.

The MINES ecu will still be mapped for 100ron fuel, UK SUL is 97, optimax is supposed to be 98.6. SO running higher boost is going to be a little suspect, a little octane booster wouldn't go amiss.

As for changing it, it can be done. I would run with a knocklink for peace of mind, and probably be inclined to run the dawes at 1.1bar held.

Paul